1. Field of the Invention
This invention relates to slitting means and in particular to perforator wheels.
2. Description of the Prior Art
In the conventional perforation of workpiece sheets, a plurality of spaced slits are provided. The nonslit portions of the sheet between the slits may then be readily torn to permit separation of the sheet when desired along the slit line. A number of different configurations for such slit tear lines has been developed. The present invention comprehends an improved structure for providing a novel tear line configuration.
Illustrative of the prior art structures is that of William M. Strange United States Letters Pat. No. 3,205,750 which shows means for perforating paperboard utilizing blades having sharp toothed edges adapted to provide a series of spaced cuts that extend completely through the thickness of the paperboard and intermediate cuts that extend only partially therethrough.
Harold W. Huffman, in United States Letters Pat. No. 3,268,136, shows a data card and method of making the same where adjacent portions of adjoining cards have finished edges common to both cards. The method further contemplates providing tear strips along the opposite edges having notches wherein the edges of primary cuts collectively constitute an end of the card with the tufts of paper stock resulting from tearing of the strip being disposed within recesses in the slit edge.
Valone V. Weyant, in United States Letters Pat. No. 3,440,915, shows a quick release connection for connecting a cutting blade to an arbor in an edge trimming apparatus.
Stanley Milton Silver, in United States Letters Pat. No. 3,463,039, shows a knife for cutting tear-lines in cardboard and the like wherein a tongue-and-groove type edge configuration is obtained by a staggered relationship of a pair of slitting blades. The tear lines are defined by a pair of cutter blades separated by a rubber spacer.
Thomas Lynch et al, in United States Letters Pat. No. 3,855,890, show a slitter/perforator apparatus having a cutting blade and a perforator blade which are arranged to be selectively utilized to provide either a cutting or perforating operation. The cutting operation produces a continuous slit whereas the perforating operation provides a discontinuous slit in the workpiece sheet.
In United States Letters Pat. No. 3,880,030 of Stanley Irving Rosengren, a rotary cutter assembly is shown having a notch cutting wheel for receiving bars.